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merikatori_9296's avatar
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Nov 01, 2011

[Newbie] Question about HA pair in real word

Hi all!



I am going to deploy F5 Big IP systems including 2 LTMs (v10) in real world. Everything is fine with LTM VE on VMware when using active/standby with network failover method and VLAN fail-safe. I have read a statement about combining network failover and hard-wired failover:




You use network failover in addition to hard-wired failover. Even with


serial cable failover configured, communication through network failover


is required for certain features to function properly, for example, the


communication that occurs over the network during failover mirroring.





I have three questions about active/standby


1. With active/standby, beside to use hard-wired failover (serial cable) with VLAN fail-safe and network mirroring, is it necessary to enable network failover?




2. In the case of active unit's VLAN down, if using VLAN fail-safe how does standby unit know to failover to active? through communication of network failover pair or hard-wired failover or configsync


(There are three areas to specify three pairs address: network failover, network mirroring, configsync.)




3. Are there any messages exchanged on serial cable or just voltage?




Thanks and Best Regards


3 Replies

  • Hi,



    It is always recommended to deploy the failover cable, with network failover, and have VLAN fail-safe as a trigger for failover. If the two devices are going to be physically further than 50ft apart, then you cannot use the failover cable, then you only use network failover, for failover.



    When you configure VLAN fail-safe, the active device will listen for traffic coming from the configured VLANs. If no traffic is coming from those VLANs, it will generate traffic..if it still has no response, it will initiate fail-over.



    The serial cable is a voltage check only. Nothing elses runs over it. Same as with network failover, it is a network pulse only.





  • LTM Virtual Edition only supports network failover. The hardware BIG-IP units additionally support serial failover.





  • what is the recommended configuration for failover now in v11 in a virtual environment? Is there a case study or solution guide that provides best practices or recommendations?